Python - rewrite byte array with 0x00 for each hex byte read in

Question

I'm currently investigating ways of bypassing basic signature detection on antivirus products. Right now, I'm trying to break up a file by padding with 0x00 (maybe NOPs are better?) but I can't figure out how to do this. I'm writing an incredibly simple Python script to automate obfuscation of binaries to bypass basic detection (to prove a point in my paper) and this is the final snippet.

So far, I've only read the executable into a bytearray, I'm now trying to figure out how I would read each hex value, write it to a new array, write 0x00, take the next hex value from the first array and continue.

Example
a = 54 68 69 73 20 70 72 6F 67 72 61 6D 20 63 61 6E 6E 6F 74 20 62 65 20 72 75 6E 20 69 6E 20 44 4F 53 20 6D 6F 64 65 (DOS stub)

I'm looking to pad/insert 00 in between each hex value to have the following

b = 54 00 68 00 69 00 73 00 20 00 70 etc.

Is there a simple way of going about this?

Answer 1

b''.join(bytes(x) for x in zip(a, itertools.repeat(0)))

Answer 2

Join you list of hex values with ' 00 ' !

# when type of a is of <type 'bytearray'> 
>>> b = ' 00 '.join(str(a).split())
>>> print b
54 00 68 00 69 00 73 00 20 00 70 00 72 00 6F 00 67 00 72 00 61 00 6D 00 20 00 63 00 61 00 6E 00 6E 00 6F 00 74 00 20 00 62 00 65 00 20 00 72 00 75 00 6E 00 20 00 69 00 6E 00 20 00 44 00 4F 00 53 00 20 00 6D 00 6F 00 64 00 65
>>> b = bytearray(b) 
>>> print b
bytearray(b'54 00 68 00 69 00 73 00 20 00 70 00 72 00 6F 00 67 00 72 00 61 00 6D 00 20 00 63 00 61 00 6E 00 6E 00 6F 00 74 00 20 00 62 00 65 00 20 00 72 00 75 00 6E 00 20 00 69 00 6E 00 20 00 44 00 4F 00 53 00 20 00 6D 00 6F 00 64 00 65')

Hope it helps!